The present invention relates to chair controls, particularly posture tilt chair controls which facilitate adjustment of a chair back relative to a chair seat.
In such mechanisms, a support arm extends generally horizontally from beneath the seat support member and a back upright support member is pivotally joined to the generally horizontal support arm. Securing means can be tightened or loosened to facilitate adjusting the angular orientation of the back support member relative to the support arm, thereby facilitating adjustment of the angle of the chair back relative to the chair seat.
Usually, the support arm itself is then pivotally joined to the seat support member and a torsion pack is employed between the two whereby one can lean back against the chair back and the entire back and back supporting mechanism will tilt rearwardly against the action of the torsion member. The torsion system, however, forms no part of the present invention.
The securing means typically comprises a bolt oriented generally horizontally and passing through both the support arm and the upright back support member. A handle on the end of the bolt or on the nut which threads onto the bolt projects laterally to one side or the other of the back upright support member.
This location for the handle is detremental to the appearance of the chair. However, while it would be more desirable to locate the handle underneath the chair in some way, the latter is a more dangerous condition in that if the bolt ever broke or disengaged the handle in some way, it would fall to the floor and the back support member would then be free to fall completely rearwardly. This could result in serious injury to a person seated in the chair at such a time.
Also, locating the handle beneath the mechanism rather than to one side may be considered by some to make it more difficult to adjust the angle of the seat back in that when the securing mechanism is loosened the seat back will tend to flop around and one will have to have one hand on the seat back and another on the handle beneath the seat back.
Heretofore, prior artisans have been unable to conceive of economical arrangements for obviating these shortcomings of prior art posture mechanisms whereby orientation of the handle on the securing means could be located beneath the mechanism rather than to one side thereof.